SQLite

**
*************************************************************************
** This file contains code used to implement the sqlite_set_authorizer()
** API.  This facility is an optional feature of the library.  Embedded
** systems that do not need this facility may omit it by recompiling
** the library with -DSQLITE_OMIT_AUTHORIZATION=1
**
** $Id: auth.c,v 1.8 2003/04/25 17:52:11 drh Exp $
*/
#include "sqliteInt.h"

/*
** All of the code in this file may be omitted by defining a single
** macro.
*/

    "SQLITE_IGNORE, or SQLITE_DENY", 0);
  pParse->nErr++;
  pParse->rc = SQLITE_MISUSE;
}

/*
** The pExpr should be a TK_COLUMN expression.  The table referred to
** is in pTabList with an offset of base.  Check to see if it is OK to read
** this particular column.
**
** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN 
** instruction into a TK_NULL.  If the auth function returns SQLITE_DENY,
** then generate an error.
*/
void sqliteAuthRead(
  Parse *pParse,        /* The parser context */
  Expr *pExpr,          /* The expression to check authorization on */
  SrcList *pTabList,    /* All table that pExpr might refer to */
  int base              /* Offset of pTabList relative to pExpr */
){
  sqlite *db = pParse->db;
  int rc;
  Table *pTab;          /* The table being read */
  const char *zCol;     /* Name of the column of the table */
  int iSrc;             /* Index in pTabList->a[] of table being read */
  const char *zDBase;   /* Name of database being accessed */

  if( db->xAuth==0 ) return;
  assert( pExpr->op==TK_COLUMN );

  iSrc = pExpr->iTable - base;

  if( iSrc>=0 && iSrc<pTabList->nSrc ){
    pTab = pTabList->a[iSrc].pTab;
  }else{
    /* This must be an attempt to read the NEW or OLD pseudo-tables
    ** of a trigger.
    */
    TriggerStack *pStack; /* The stack of current triggers */

**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.151 2003/05/01 16:56:03 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Check to see if the schema for the database needs

      sqliteVdbeAddOp(v, OP_Rewind, 2, lbl2);
      lbl1 = sqliteVdbeAddOp(v, OP_Recno, 2, 0);
      for(i=0; i<pIndex->nColumn; i++){
        int iCol = pIndex->aiColumn[i];
        if( pTab->iPKey==iCol ){
          sqliteVdbeAddOp(v, OP_Dup, i, 0);
        }else{
          sqliteVdbeAddOp(v, OP_Column, 2, pIndex->aiColumn[i]);
        }
      }
      sqliteVdbeAddOp(v, OP_MakeIdxKey, pIndex->nColumn, 0);
      if( db->file_format>=4 ) sqliteAddIdxKeyType(v, pIndex);
      sqliteVdbeAddOp(v, OP_IdxPut, 1, pIndex->onError!=OE_None);
      sqliteVdbeChangeP3(v, -1, "indexed columns are not unique", P3_STATIC);
      sqliteVdbeAddOp(v, OP_Next, 2, lbl1);

/*
** Assign cursors to all tables in a SrcList
*/
void sqliteSrcListAssignCursors(Parse *pParse, SrcList *pList){
  int i;
  for(i=0; i<pList->nSrc; i++){
    if( pList->a[i].iCursor<0 ){
      pList->a[i].iCursor = ++pParse->nTab;
    }
  }
}

/*
** Add an alias to the last identifier on the given identifier list.
*/

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle DELETE FROM statements.
**
** $Id: delete.c,v 1.55 2003/04/25 17:52:11 drh Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.

  Vdbe *v;               /* The virtual database engine */
  Table *pTab;           /* The table from which records will be deleted */
  const char *zDb;       /* Name of database holding pTab */
  int end, addr;         /* A couple addresses of generated code */
  int i;                 /* Loop counter */
  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Index *pIdx;           /* For looping over indices of the table */
  int base;              /* Index of the first available table cursor */
  sqlite *db;            /* Main database structure */
  int isView;            /* True if attempting to delete from a view */
  AuthContext sContext;  /* Authorization context */

  int row_triggers_exist = 0;  /* True if any triggers exist */
  int before_triggers;         /* True if there are BEFORE triggers */
  int after_triggers;          /* True if there are AFTER triggers */

  */
  if( row_triggers_exist ){ 
    oldIdx = pParse->nTab++;
  }

  /* Resolve the column names in all the expressions.
  */

  base = pParse->nTab++;
  if( pWhere ){
    if( sqliteExprResolveIds(pParse, base, pTabList, 0, pWhere) ){
      goto delete_from_cleanup;
    }
    if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
      goto delete_from_cleanup;
    }
  }

       !row_triggers_exist && pTab->iDb==1);

  /* If we are trying to delete from a view, construct that view into
  ** a temporary table.
  */
  if( isView ){
    Select *pView = sqliteSelectDup(pTab->pSelect);
    sqliteSelect(pParse, pView, SRT_TempTable, base, 0, 0, 0);
    sqliteSelectDelete(pView);
  }

  /* Initialize the counter of the number of rows deleted, if
  ** we are counting rows.
  */
  if( db->flags & SQLITE_CountRows ){

    if( db->flags & SQLITE_CountRows ){
      /* If counting rows deleted, just count the total number of
      ** entries in the table. */
      int endOfLoop = sqliteVdbeMakeLabel(v);
      int addr;
      if( !isView ){
        sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);
        sqliteVdbeAddOp(v, OP_OpenRead, base, pTab->tnum);
      }
      sqliteVdbeAddOp(v, OP_Rewind, base, sqliteVdbeCurrentAddr(v)+2);
      addr = sqliteVdbeAddOp(v, OP_AddImm, 1, 0);
      sqliteVdbeAddOp(v, OP_Next, base, addr);
      sqliteVdbeResolveLabel(v, endOfLoop);
      sqliteVdbeAddOp(v, OP_Close, base, 0);
    }
    if( !isView ){
      sqliteVdbeAddOp(v, OP_Clear, pTab->tnum, pTab->iDb);
      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
        sqliteVdbeAddOp(v, OP_Clear, pIdx->tnum, pIdx->iDb);
      }
    }
  }

  /* The usual case: There is a WHERE clause so we have to scan through
  ** the table an pick which records to delete.
  */
  else{
    /* Begin the database scan
    */
    pWInfo = sqliteWhereBegin(pParse, base, pTabList, pWhere, 1, 0);
    if( pWInfo==0 ) goto delete_from_cleanup;

    /* Remember the key of every item to be deleted.
    */
    sqliteVdbeAddOp(v, OP_ListWrite, 0, 0);
    if( db->flags & SQLITE_CountRows ){
      sqliteVdbeAddOp(v, OP_AddImm, 1, 0);

    ** row triggers.
    */
    if( row_triggers_exist ){
      addr = sqliteVdbeAddOp(v, OP_ListRead, 0, end);
      sqliteVdbeAddOp(v, OP_Dup, 0, 0);
      if( !isView ){
        sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);
        sqliteVdbeAddOp(v, OP_OpenRead, base, pTab->tnum);
      }
      sqliteVdbeAddOp(v, OP_MoveTo, base, 0);

      sqliteVdbeAddOp(v, OP_Recno, base, 0);
      sqliteVdbeAddOp(v, OP_RowData, base, 0);
      sqliteVdbeAddOp(v, OP_PutIntKey, oldIdx, 0);
      if( !isView ){
        sqliteVdbeAddOp(v, OP_Close, base, 0);
      }

      sqliteCodeRowTrigger(pParse, TK_DELETE, 0, TK_BEFORE, pTab, -1, 
          oldIdx, (pParse->trigStack)?pParse->trigStack->orconf:OE_Default,
	  addr);
    }

    if( !isView ){
      /* Open cursors for the table we are deleting from and all its
      ** indices.  If there are row triggers, this happens inside the
      ** OP_ListRead loop because the cursor have to all be closed
      ** before the trigger fires.  If there are no row triggers, the
      ** cursors are opened only once on the outside the loop.
      */
      pParse->nTab = base + 1;
      sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);
      sqliteVdbeAddOp(v, OP_OpenWrite, base, pTab->tnum);
      for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
        sqliteVdbeAddOp(v, OP_Integer, pIdx->iDb, 0);
        sqliteVdbeAddOp(v, OP_OpenWrite, pParse->nTab++, pIdx->tnum);
      }

      /* This is the beginning of the delete loop when there are no
      ** row triggers */
      if( !row_triggers_exist ){ 
        addr = sqliteVdbeAddOp(v, OP_ListRead, 0, end);
      }

      /* Delete the row */
      sqliteGenerateRowDelete(db, v, pTab, base, pParse->trigStack==0);
    }

    /* If there are row triggers, close all cursors then invoke
    ** the AFTER triggers
    */
    if( row_triggers_exist ){
      if( !isView ){
        for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
          sqliteVdbeAddOp(v, OP_Close, base + i, pIdx->tnum);
        }
        sqliteVdbeAddOp(v, OP_Close, base, 0);
      }
      sqliteCodeRowTrigger(pParse, TK_DELETE, 0, TK_AFTER, pTab, -1, 
          oldIdx, (pParse->trigStack)?pParse->trigStack->orconf:OE_Default,
	  addr);
    }

    /* End of the delete loop */
    sqliteVdbeAddOp(v, OP_Goto, 0, addr);
    sqliteVdbeResolveLabel(v, end);
    sqliteVdbeAddOp(v, OP_ListReset, 0, 0);

    /* Close the cursors after the loop if there are no row triggers */
    if( !row_triggers_exist ){
      for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
        sqliteVdbeAddOp(v, OP_Close, base + i, pIdx->tnum);
      }
      sqliteVdbeAddOp(v, OP_Close, base, 0);
      pParse->nTab = base;
    }
  }
  sqliteEndWriteOperation(pParse);

  /*
  ** Return the number of rows that were deleted.
  */

** and then generates code to remove both the table record and all index
** entries that point to that record.
*/
void sqliteGenerateRowDelete(
  sqlite *db,        /* The database containing the index */
  Vdbe *v,           /* Generate code into this VDBE */
  Table *pTab,       /* Table containing the row to be deleted */
  int base,          /* Cursor number for the table */
  int count          /* Increment the row change counter */
){
  int addr;
  addr = sqliteVdbeAddOp(v, OP_NotExists, base, 0);
  sqliteGenerateRowIndexDelete(db, v, pTab, base, 0);
  sqliteVdbeAddOp(v, OP_Delete, base, count);
  sqliteVdbeChangeP2(v, addr, sqliteVdbeCurrentAddr(v));
}

/*
** This routine generates VDBE code that causes the deletion of all
** index entries associated with a single row of a single table.
**
** The VDBE must be in a particular state when this routine is called.
** These are the requirements:
**
**   1.  A read/write cursor pointing to pTab, the table containing the row
**       to be deleted, must be opened as cursor number "base".
**
**   2.  Read/write cursors for all indices of pTab must be open as
**       cursor number base+i for the i-th index.
**
**   3.  The "base" cursor must be pointing to the row that is to be
**       deleted.
*/
void sqliteGenerateRowIndexDelete(
  sqlite *db,        /* The database containing the index */
  Vdbe *v,           /* Generate code into this VDBE */
  Table *pTab,       /* Table containing the row to be deleted */
  int base,          /* Cursor number for the table */
  char *aIdxUsed     /* Only delete if aIdxUsed!=0 && aIdxUsed[i]!=0 */
){
  int i;
  Index *pIdx;

  for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
    int j;
    if( aIdxUsed!=0 && aIdxUsed[i-1]==0 ) continue;
    sqliteVdbeAddOp(v, OP_Recno, base, 0);
    for(j=0; j<pIdx->nColumn; j++){
      int idx = pIdx->aiColumn[j];
      if( idx==pTab->iPKey ){
        sqliteVdbeAddOp(v, OP_Dup, j, 0);
      }else{
        sqliteVdbeAddOp(v, OP_Column, base, idx);
      }
    }
    sqliteVdbeAddOp(v, OP_MakeIdxKey, pIdx->nColumn, 0);
    if( db->file_format>=4 ) sqliteAddIdxKeyType(v, pIdx);
    sqliteVdbeAddOp(v, OP_IdxDelete, base+i, 0);
  }
}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.94 2003/04/22 20:30:39 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Construct a new expression node and return a pointer to it.  Memory
** for this node is obtained from sqliteMalloc().  The calling function

  pNew = sqliteMalloc( nByte );
  if( pNew==0 ) return 0;
  pNew->nSrc = p->nSrc;
  for(i=0; i<p->nSrc; i++){
    pNew->a[i].zName = sqliteStrDup(p->a[i].zName);
    pNew->a[i].zAlias = sqliteStrDup(p->a[i].zAlias);
    pNew->a[i].jointype = p->a[i].jointype;

    pNew->a[i].pTab = 0;
    pNew->a[i].pSelect = sqliteSelectDup(p->a[i].pSelect);
    pNew->a[i].pOn = sqliteExprDup(p->a[i].pOn);
    pNew->a[i].pUsing = sqliteIdListDup(p->a[i].pUsing);
  }
  return pNew;
}

** into a memory cell.
**
** Unknown columns or tables provoke an error.  The function returns
** the number of errors seen and leaves an error message on pParse->zErrMsg.
*/
int sqliteExprResolveIds(
  Parse *pParse,     /* The parser context */
  int base,          /* VDBE cursor number for first entry in pTabList */
  SrcList *pTabList, /* List of tables used to resolve column names */
  ExprList *pEList,  /* List of expressions used to resolve "AS" */
  Expr *pExpr        /* The expression to be analyzed. */
){


  if( pExpr==0 || pTabList==0 ) return 0;
  assert( base+pTabList->nSrc<=pParse->nTab );


  switch( pExpr->op ){
    /* Double-quoted strings (ex: "abc") are used as identifiers if
    ** possible.  Otherwise they remain as strings.  Single-quoted
    ** strings (ex: 'abc') are always string literals.
    */
    case TK_STRING: {
      if( pExpr->token.z[0]=='\'' ) break;

    **         a SELECT statement.  (For example, match against 'x' in
    **         "SELECT a+b AS 'x' FROM t1".)
    **
    **     3.  One of the special names "ROWID", "OID", or "_ROWID_".
    */
    case TK_ID: {
      int cnt = 0;      /* Number of matches */
      int i;            /* Loop counter */
      char *z;
      int iDb = -1;

      assert( pExpr->token.z );
      z = sqliteStrNDup(pExpr->token.z, pExpr->token.n);
      sqliteDequote(z);
      if( z==0 ) return 1;
      for(i=0; i<pTabList->nSrc; i++){
        int j;
        Table *pTab = pTabList->a[i].pTab;
        if( pTab==0 ) continue;
        iDb = pTab->iDb;
        assert( pTab->nCol>0 );
        for(j=0; j<pTab->nCol; j++){
          if( sqliteStrICmp(pTab->aCol[j].zName, z)==0 ){
            cnt++;
            pExpr->iTable = i + base;
            pExpr->iDb = pTab->iDb;
            if( j==pTab->iPKey ){
              /* Substitute the record number for the INTEGER PRIMARY KEY */
              pExpr->iColumn = -1;
              pExpr->dataType = SQLITE_SO_NUM;
            }else{
              pExpr->iColumn = j;

            pExpr->iColumn = j;
            pExpr->pLeft = sqliteExprDup(pEList->a[j].pExpr);
          }
        } 
      }
      if( cnt==0 && iDb>=0 && sqliteIsRowid(z) ){
        pExpr->iColumn = -1;
        pExpr->iTable = base;
        pExpr->iDb = iDb;
        cnt = 1 + (pTabList->nSrc>1);
        pExpr->op = TK_COLUMN;
        pExpr->dataType = SQLITE_SO_NUM;
      }
      sqliteFree(z);
      if( cnt==0 && pExpr->token.z[0]!='"' ){
        sqliteErrorMsg(pParse, "no such column: %T", &pExpr->token);
        return 1;
      }else if( cnt>1 ){
        sqliteErrorMsg(pParse, "ambiguous column name: %T", &pExpr->token);
        return 1;
      }
      if( pExpr->op==TK_COLUMN ){
        sqliteAuthRead(pParse, pExpr, pTabList, base);
      }
      break; 
    }
  
    /* A table name and column name:     ID.ID
    ** Or a database, table and column:  ID.ID.ID
    */

          zTab = pTab->zName;
          if( zTab==0 || sqliteStrICmp(zTab, zLeft)!=0 ) continue;
          if( zDb!=0 && sqliteStrICmp(db->aDb[pTab->iDb].zName, zDb)!=0 ){
            continue;
          }
        }
        if( 0==(cntTab++) ){
          pExpr->iTable = i + base;
          pExpr->iDb = pTab->iDb;
        }
        for(j=0; j<pTab->nCol; j++){
          if( sqliteStrICmp(pTab->aCol[j].zName, zRight)==0 ){
            cnt++;
            pExpr->iTable = i + base;
            pExpr->iDb = pTab->iDb;
            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
            pExpr->dataType = pTab->aCol[j].sortOrder & SQLITE_SO_TYPEMASK;
          }
        }
      }

        return 1;
      }
      sqliteExprDelete(pExpr->pLeft);
      pExpr->pLeft = 0;
      sqliteExprDelete(pExpr->pRight);
      pExpr->pRight = 0;
      pExpr->op = TK_COLUMN;
      sqliteAuthRead(pParse, pExpr, pTabList, base);
      break;
    }

    case TK_IN: {
      Vdbe *v = sqliteGetVdbe(pParse);
      if( v==0 ) return 1;
      if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pExpr->pLeft) ){
        return 1;
      }
      if( pExpr->pSelect ){
        /* Case 1:     expr IN (SELECT ...)
        **
        ** Generate code to write the results of the select into a temporary
        ** table.  The cursor number of the temporary table has already

      }
      break;
    }

    /* For all else, just recursively walk the tree */
    default: {
      if( pExpr->pLeft
      && sqliteExprResolveIds(pParse, base, pTabList, pEList, pExpr->pLeft) ){
        return 1;
      }
      if( pExpr->pRight 
      && sqliteExprResolveIds(pParse, base, pTabList, pEList, pExpr->pRight) ){
        return 1;
      }
      if( pExpr->pList ){
        int i;
        ExprList *pList = pExpr->pList;
        for(i=0; i<pList->nExpr; i++){
          Expr *pArg = pList->a[i].pExpr;
          if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pArg) ){
            return 1;
          }
        }
      }
    }
  }
  return 0;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.82 2003/04/24 01:45:04 drh Exp $
*/
#include "sqliteInt.h"

/*
** This routine is call to handle SQL of the following forms:
**
**    insert into TABLE (IDLIST) values(EXPRLIST)

  Table *pTab;          /* The table to insert into */
  char *zTab;           /* Name of the table into which we are inserting */
  const char *zDb;      /* Name of the database holding this table */
  int i, j, idx;        /* Loop counters */
  Vdbe *v;              /* Generate code into this virtual machine */
  Index *pIdx;          /* For looping over indices of the table */
  int nColumn;          /* Number of columns in the data */
  int base;             /* First available cursor */
  int iCont, iBreak;    /* Beginning and end of the loop over srcTab */
  sqlite *db;           /* The main database structure */
  int keyColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
  int endOfLoop;        /* Label for the end of the insertion loop */
  int useTempTable;     /* Store SELECT results in intermediate table */
  int srcTab;           /* Data comes from this temporary cursor if >=0 */
  int iSelectLoop;      /* Address of code that implements the SELECT */

    assert( pList!=0 );
    srcTab = -1;
    useTempTable = 0;
    assert( pList );
    nColumn = pList->nExpr;
    dummy.nSrc = 0;
    for(i=0; i<nColumn; i++){
      if( sqliteExprResolveIds(pParse, 0, &dummy, 0, pList->a[i].pExpr) ){
        goto insert_cleanup;
      }
      if( sqliteExprCheck(pParse, pList->a[i].pExpr, 0, 0) ){
        goto insert_cleanup;
      }
    }
  }

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.135 2003/04/29 16:20:46 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.

** that uses that table becomes part of the ON clause for the join.
**
** It is important to enphasize that this is not exactly how oracle8
** works.  But it is close enough so that one can construct queries that
** will work correctly for both SQLite and Oracle8.
*/
static int sqliteOracle8JoinFixup(
  int base,         /* VDBE cursor number for first table in pSrc */
  SrcList *pSrc,    /* List of tables being joined */
  Expr *pWhere      /* The WHERE clause of the SELECT statement */
){
  int rc = 0;
  if( ExprHasProperty(pWhere, EP_Oracle8Join) && pWhere->op==TK_COLUMN ){
    int idx = pWhere->iTable - base;



    assert( idx>=0 && idx<pSrc->nSrc );
    if( idx>0 ){
      pSrc->a[idx-1].jointype &= ~JT_INNER;
      pSrc->a[idx-1].jointype |= JT_OUTER|JT_LEFT;
      return 1;
    }
  }
  if( pWhere->pRight ){
    rc = sqliteOracle8JoinFixup(base, pSrc, pWhere->pRight);
  }
  if( pWhere->pLeft ){
    rc |= sqliteOracle8JoinFixup(base, pSrc, pWhere->pLeft);
  }
  if( pWhere->pList ){
    int i;
    ExprList *pList = pWhere->pList;
    for(i=0; i<pList->nExpr && rc==0; i++){
      rc |= sqliteOracle8JoinFixup(base, pSrc, pList->a[i].pExpr);
    }
  }
  if( rc==1 && (pWhere->op==TK_AND || pWhere->op==TK_EQ) ){
    setJoinExpr(pWhere);
    rc = 0;
  }
  return rc;

** The "datatype" for a result that is a column of a type is the
** datatype definition extracted from the CREATE TABLE statement.
** The datatype for an expression is either TEXT or NUMERIC.  The
** datatype for a ROWID field is INTEGER.
*/
static void generateColumnTypes(
  Parse *pParse,      /* Parser context */
  int base,           /* VDBE cursor corresponding to first entry in pTabList */
  SrcList *pTabList,  /* List of tables */
  ExprList *pEList    /* Expressions defining the result set */
){
  Vdbe *v = pParse->pVdbe;
  int i;
  if( pParse->useCallback && (pParse->db->flags & SQLITE_ReportTypes)==0 ){
    return;
  }
  for(i=0; i<pEList->nExpr; i++){
    Expr *p = pEList->a[i].pExpr;
    char *zType = 0;
    if( p==0 ) continue;
    if( p->op==TK_COLUMN && pTabList ){
      Table *pTab = pTabList->a[p->iTable - base].pTab;
      int iCol = p->iColumn;



      if( iCol<0 ) iCol = pTab->iPKey;
      assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
      if( iCol<0 ){
        zType = "INTEGER";
      }else{
        zType = pTab->aCol[iCol].zType;
      }

/*
** Generate code that will tell the VDBE the names of columns
** in the result set.  This information is used to provide the
** azCol[] vaolues in the callback.
*/
static void generateColumnNames(
  Parse *pParse,      /* Parser context */
  int base,           /* VDBE cursor corresponding to first entry in pTabList */
  SrcList *pTabList,  /* List of tables */
  ExprList *pEList    /* Expressions defining the result set */
){
  Vdbe *v = pParse->pVdbe;
  int i;
  if( pParse->colNamesSet || v==0 || sqlite_malloc_failed ) return;
  pParse->colNamesSet = 1;
  for(i=0; i<pEList->nExpr; i++){
    Expr *p;
    char *zType = 0;
    int showFullNames;
    p = pEList->a[i].pExpr;
    if( p==0 ) continue;
    if( pEList->a[i].zName ){
      char *zName = pEList->a[i].zName;
      sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
      sqliteVdbeChangeP3(v, -1, zName, strlen(zName));
      continue;
    }
    showFullNames = (pParse->db->flags & SQLITE_FullColNames)!=0;
    if( p->op==TK_COLUMN && pTabList ){
      Table *pTab = pTabList->a[p->iTable - base].pTab;
      char *zCol;
      int iCol = p->iColumn;



      if( iCol<0 ) iCol = pTab->iPKey;
      assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
      if( iCol<0 ){
        zCol = "_ROWID_";
        zType = "INTEGER";
      }else{
        zCol = pTab->aCol[iCol].zName;
        zType = pTab->aCol[iCol].zType;
      }
      if( p->span.z && p->span.z[0] && !showFullNames ){
        int addr = sqliteVdbeAddOp(v,OP_ColumnName, i, 0);
        sqliteVdbeChangeP3(v, -1, p->span.z, p->span.n);
        sqliteVdbeCompressSpace(v, addr);
      }else if( pTabList->nSrc>1 || showFullNames ){
        char *zName = 0;
        char *zTab;
 
        zTab = pTabList->a[p->iTable - base].zAlias;
        if( showFullNames || zTab==0 ) zTab = pTab->zName;
        sqliteSetString(&zName, zTab, ".", zCol, 0);
        sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
        sqliteVdbeChangeP3(v, -1, zName, strlen(zName));
        sqliteFree(zName);
      }else{
        sqliteVdbeAddOp(v, OP_ColumnName, i, 0);

      /* Convert the data in the temporary table into whatever form
      ** it is that we currently need.
      */      
      if( eDest!=priorOp || unionTab!=iParm ){
        int iCont, iBreak, iStart;
        assert( p->pEList );
        if( eDest==SRT_Callback ){
          generateColumnNames(pParse, p->base, 0, p->pEList);
          generateColumnTypes(pParse, p->base, p->pSrc, p->pEList);
        }
        iBreak = sqliteVdbeMakeLabel(v);
        iCont = sqliteVdbeMakeLabel(v);
        sqliteVdbeAddOp(v, OP_Rewind, unionTab, iBreak);
        iStart = sqliteVdbeCurrentAddr(v);
        multiSelectSortOrder(p, p->pOrderBy);
        rc = selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,

      if( rc ) return rc;

      /* Generate code to take the intersection of the two temporary
      ** tables.
      */
      assert( p->pEList );
      if( eDest==SRT_Callback ){
        generateColumnNames(pParse, p->base, 0, p->pEList);
        generateColumnTypes(pParse, p->base, p->pSrc, p->pEList);
      }
      iBreak = sqliteVdbeMakeLabel(v);
      iCont = sqliteVdbeMakeLabel(v);
      sqliteVdbeAddOp(v, OP_Rewind, tab1, iBreak);
      iStart = sqliteVdbeAddOp(v, OP_FullKey, tab1, 0);
      sqliteVdbeAddOp(v, OP_NotFound, tab2, iCont);
      multiSelectSortOrder(p, p->pOrderBy);

    (pParse->useCallback==0 || (pParse->db->flags & SQLITE_NullCallback)!=0)
  ){
    sqliteVdbeAddOp(v, OP_NullCallback, p->pEList->nExpr, 0);
  }
  return 0;
}

/*
** Recursively scan through an expression tree.  For every reference
** to a column in table number iFrom, change that reference to the
** same column in table number iTo.
*/
static void changeTablesInList(ExprList*, int, int);  /* Forward Declaration */
static void changeTables(Expr *pExpr, int iFrom, int iTo){
  if( pExpr==0 ) return;
  if( pExpr->op==TK_COLUMN && pExpr->iTable==iFrom ){
    pExpr->iTable = iTo;
  }else{
    changeTables(pExpr->pLeft, iFrom, iTo);
    changeTables(pExpr->pRight, iFrom, iTo);
    changeTablesInList(pExpr->pList, iFrom, iTo);
  }
}
static void changeTablesInList(ExprList *pList, int iFrom, int iTo){
  if( pList ){
    int i;
    for(i=0; i<pList->nExpr; i++){
      changeTables(pList->a[i].pExpr, iFrom, iTo);
    }
  }
}

/*
** Scan through the expression pExpr.  Replace every reference to
** a column in table number iTable with a copy of the corresponding
** entry in pEList.  (But leave references to the ROWID column 
** unchanged.)  When making a copy of an expression in pEList, change
** references to columns in table iSub into references to table iTable.
**
** This routine is part of the flattening procedure.  A subquery
** whose result set is defined by pEList appears as entry in the
** FROM clause of a SELECT such that the VDBE cursor assigned to that
** FORM clause entry is iTable.  This routine make the necessary 
** changes to pExpr so that it refers directly to the source table
** of the subquery rather the result set of the subquery.
*/
static void substExprList(ExprList*,int,ExprList*,int);  /* Forward Decl */
static void substExpr(Expr *pExpr, int iTable, ExprList *pEList, int iSub){
  if( pExpr==0 ) return;
  if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable && pExpr->iColumn>=0 ){
    Expr *pNew;
    assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
    assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
    pNew = pEList->a[pExpr->iColumn].pExpr;
    assert( pNew!=0 );
    pExpr->op = pNew->op;
    pExpr->dataType = pNew->dataType;
    assert( pExpr->pLeft==0 );
    pExpr->pLeft = sqliteExprDup(pNew->pLeft);
    assert( pExpr->pRight==0 );
    pExpr->pRight = sqliteExprDup(pNew->pRight);
    assert( pExpr->pList==0 );
    pExpr->pList = sqliteExprListDup(pNew->pList);
    pExpr->iTable = pNew->iTable;
    pExpr->iColumn = pNew->iColumn;
    pExpr->iAgg = pNew->iAgg;
    sqliteTokenCopy(&pExpr->token, &pNew->token);
    sqliteTokenCopy(&pExpr->span, &pNew->span);
    if( iSub!=iTable ){
      changeTables(pExpr, iSub, iTable);
    }
  }else{
    substExpr(pExpr->pLeft, iTable, pEList, iSub);
    substExpr(pExpr->pRight, iTable, pEList, iSub);
    substExprList(pExpr->pList, iTable, pEList, iSub);
  }
}
static void 
substExprList(ExprList *pList, int iTable, ExprList *pEList, int iSub){
  int i;
  if( pList==0 ) return;
  for(i=0; i<pList->nExpr; i++){
    substExpr(pList->a[i].pExpr, iTable, pEList, iSub);
  }
}

/*
** This routine attempts to flatten subqueries in order to speed
** execution.  It returns 1 if it makes changes and 0 if no flattening
** occurs.

  int isAgg,           /* True if outer SELECT uses aggregate functions */
  int subqueryIsAgg    /* True if the subquery uses aggregate functions */
){
  Select *pSub;       /* The inner query or "subquery" */
  SrcList *pSrc;      /* The FROM clause of the outer query */
  SrcList *pSubSrc;   /* The FROM clause of the subquery */
  ExprList *pList;    /* The result set of the outer query */

  int i;
  int iParent, iSub;
  Expr *pWhere;

  /* Check to see if flattening is permitted.  Return 0 if not.
  */
  if( p==0 ) return 0;
  pSrc = p->pSrc;
  assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );

  }
  if( (p->isDistinct || p->nLimit>=0) && subqueryIsAgg ) return 0;
  if( p->pOrderBy && pSub->pOrderBy ) return 0;

  /* If we reach this point, it means flattening is permitted for the
  ** iFrom-th entry of the FROM clause in the outer query.
  */
  iParent = p->base + iFrom;
  iSub = pSub->base;
  substExprList(p->pEList, iParent, pSub->pEList, iSub);
  pList = p->pEList;
  for(i=0; i<pList->nExpr; i++){
    Expr *pExpr;
    if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
      pList->a[i].zName = sqliteStrNDup(pExpr->span.z, pExpr->span.n);
    }
  }
  if( isAgg ){
    substExprList(p->pGroupBy, iParent, pSub->pEList, iSub);
    substExpr(p->pHaving, iParent, pSub->pEList, iSub);
  }
  if( pSub->pOrderBy ){
    assert( p->pOrderBy==0 );
    p->pOrderBy = pSub->pOrderBy;
    pSub->pOrderBy = 0;
    changeTablesInList(p->pOrderBy, iSub, iParent);
  }else if( p->pOrderBy ){
    substExprList(p->pOrderBy, iParent, pSub->pEList, iSub);
  }
  if( pSub->pWhere ){
    pWhere = sqliteExprDup(pSub->pWhere);
    if( iParent!=iSub ){
      changeTables(pWhere, iSub, iParent);
    }
  }else{
    pWhere = 0;
  }
  if( subqueryIsAgg ){
    assert( p->pHaving==0 );
    p->pHaving = p->pWhere;
    p->pWhere = pWhere;
    substExpr(p->pHaving, iParent, pSub->pEList, iSub);
    if( pSub->pHaving ){
      Expr *pHaving = sqliteExprDup(pSub->pHaving);
      if( iParent!=iSub ){
        changeTables(pHaving, iSub, iParent);
      }
      if( p->pHaving ){
        p->pHaving = sqliteExpr(TK_AND, p->pHaving, pHaving, 0);
      }else{
        p->pHaving = pHaving;
      }
    }
    assert( p->pGroupBy==0 );
    p->pGroupBy = sqliteExprListDup(pSub->pGroupBy);
    if( iParent!=iSub ){
      changeTablesInList(p->pGroupBy, iSub, iParent);
    }
  }else if( p->pWhere==0 ){
    p->pWhere = pWhere;
  }else{
    substExpr(p->pWhere, iParent, pSub->pEList, iSub);
    if( pWhere ){
      p->pWhere = sqliteExpr(TK_AND, p->pWhere, pWhere, 0);
    }
  }
  p->isDistinct = p->isDistinct || pSub->isDistinct;

  if( pSub->nLimit>=0 ){
    if( p->nLimit<0 ){
      p->nLimit = pSub->nLimit;
    }else if( p->nLimit+p->nOffset > pSub->nLimit+pSub->nOffset ){
      p->nLimit = pSub->nLimit + pSub->nOffset - p->nOffset;
    }
  }
  p->nOffset += pSub->nOffset;

  /* If the subquery contains subqueries of its own, that were not
  ** flattened, then code will have already been generated to put
  ** the results of those sub-subqueries into VDBE cursors relative
  ** to the subquery.  We must translate the cursor number into values
  ** suitable for use by the outer query.
  */
  for(i=0; i<pSubSrc->nSrc; i++){
    Vdbe *v;
    if( pSubSrc->a[i].pSelect==0 ) continue;
    v = sqliteGetVdbe(pParse);
    sqliteVdbeAddOp(v, OP_RenameCursor, pSub->base+i, p->base+i);
  }

  if( pSrc->a[iFrom].pTab && pSrc->a[iFrom].pTab->isTransient ){
    sqliteDeleteTable(0, pSrc->a[iFrom].pTab);
  }
  pSrc->a[iFrom].pTab = pSubSrc->a[0].pTab;
  pSubSrc->a[0].pTab = 0;
  assert( pSrc->a[iFrom].pSelect==pSub );
  pSrc->a[iFrom].pSelect = pSubSrc->a[0].pSelect;

  /* Identify column names if we will be using the callback.  This
  ** step is skipped if the output is going to a table or a memory cell.
  */
  v = sqliteGetVdbe(pParse);
  if( v==0 ) return 0;
  if( eDest==SRT_Callback ){
    generateColumnNames(pParse, p->base, p->pSrc, p->pEList);
    generateColumnTypes(pParse, p->base, p->pSrc, p->pEList);
  }

  /* Generating code to find the min or the max.  Basically all we have
  ** to do is find the first or the last entry in the chosen index.  If
  ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
  ** or last entry in the main table.
  */
  if( !pParse->schemaVerified && (pParse->db->flags & SQLITE_InTrans)==0 ){
    sqliteCodeVerifySchema(pParse);
  }
  base = p->base;
  sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);
  sqliteVdbeAddOp(v, OP_OpenRead, base, pTab->tnum);
  sqliteVdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
  cont = sqliteVdbeMakeLabel(v);
  if( pIdx==0 ){
    sqliteVdbeAddOp(v, seekOp, base, 0);
  }else{

  SrcList *pTabList;     /* List of tables to select from */
  Expr *pWhere;          /* The WHERE clause.  May be NULL */
  ExprList *pOrderBy;    /* The ORDER BY clause.  May be NULL */
  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
  Expr *pHaving;         /* The HAVING clause.  May be NULL */
  int isDistinct;        /* True if the DISTINCT keyword is present */
  int distinct;          /* Table to use for the distinct set */
  int base;              /* First cursor available for use */
  int rc = 1;            /* Value to return from this function */

  if( sqlite_malloc_failed || pParse->nErr || p==0 ) return 1;
  if( sqliteAuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;

  /* If there is are a sequence of queries, do the earlier ones first.
  */
  if( p->pPrior ){
    return multiSelect(pParse, p, eDest, iParm);
  }

  /* Make local copies of the parameters for this query.
  */
  pTabList = p->pSrc;
  pWhere = p->pWhere;
  pOrderBy = p->pOrderBy;
  pGroupBy = p->pGroupBy;
  pHaving = p->pHaving;
  isDistinct = p->isDistinct;

  /* Allocate a block of VDBE cursors, one for each table in the FROM clause.
  ** The WHERE processing requires that the cursors for the tables in the
  ** FROM clause be consecutive.
  */
  base = p->base = pParse->nTab;
  pParse->nTab += pTabList->nSrc;

  /* 
  ** Do not even attempt to generate any code if we have already seen
  ** errors before this routine starts.
  */
  if( pParse->nErr>0 ) goto select_end;

  /* At this point, we should have allocated all the cursors that we
  ** need to handle subquerys and temporary tables.  
  **
  ** Resolve the column names and do a semantics check on all the expressions.
  */
  for(i=0; i<pEList->nExpr; i++){
    if( sqliteExprResolveIds(pParse, base, pTabList, 0, pEList->a[i].pExpr) ){
      goto select_end;
    }
    if( sqliteExprCheck(pParse, pEList->a[i].pExpr, 1, &isAgg) ){
      goto select_end;
    }
  }
  if( pWhere ){
    if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pWhere) ){
      goto select_end;
    }
    if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
      goto select_end;
    }
    sqliteOracle8JoinFixup(base, pTabList, pWhere);
  }
  if( pHaving ){
    if( pGroupBy==0 ){
      sqliteErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
      goto select_end;
    }
    if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pHaving) ){
      goto select_end;
    }
    if( sqliteExprCheck(pParse, pHaving, 1, &isAgg) ){
      goto select_end;
    }
  }
  if( pOrderBy ){
    for(i=0; i<pOrderBy->nExpr; i++){
      int iCol;
      Expr *pE = pOrderBy->a[i].pExpr;
      if( sqliteExprIsInteger(pE, &iCol) && iCol>0 && iCol<=pEList->nExpr ){
        sqliteExprDelete(pE);
        pE = pOrderBy->a[i].pExpr = sqliteExprDup(pEList->a[iCol-1].pExpr);
      }
      if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pE) ){
        goto select_end;
      }
      if( sqliteExprCheck(pParse, pE, isAgg, 0) ){
        goto select_end;
      }
      if( sqliteExprIsConstant(pE) ){
        if( sqliteExprIsInteger(pE, &iCol)==0 ){

    for(i=0; i<pGroupBy->nExpr; i++){
      int iCol;
      Expr *pE = pGroupBy->a[i].pExpr;
      if( sqliteExprIsInteger(pE, &iCol) && iCol>0 && iCol<=pEList->nExpr ){
        sqliteExprDelete(pE);
        pE = pGroupBy->a[i].pExpr = sqliteExprDup(pEList->a[iCol-1].pExpr);
      }
      if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pE) ){
        goto select_end;
      }
      if( sqliteExprCheck(pParse, pE, isAgg, 0) ){
        goto select_end;
      }
      if( sqliteExprIsConstant(pE) ){
        if( sqliteExprIsInteger(pE, &iCol)==0 ){

  v = sqliteGetVdbe(pParse);
  if( v==0 ) goto select_end;

  /* Identify column names if we will be using them in a callback.  This
  ** step is skipped if the output is going to some other destination.
  */
  if( eDest==SRT_Callback ){
    generateColumnNames(pParse, p->base, pTabList, pEList);
  }

  /* Set the limiter
  */
  if( p->nLimit<=0 ){
    p->nLimit = -1;
    p->nOffset = 0;

  for(i=0; i<pTabList->nSrc; i++){
    const char *zSavedAuthContext;
    if( pTabList->a[i].pSelect==0 ) continue;
    if( pTabList->a[i].zName!=0 ){
      zSavedAuthContext = pParse->zAuthContext;
      pParse->zAuthContext = pTabList->a[i].zName;
    }
    sqliteSelect(pParse, pTabList->a[i].pSelect, SRT_TempTable, base+i,
                 p, i, &isAgg);
    if( pTabList->a[i].zName!=0 ){
      pParse->zAuthContext = zSavedAuthContext;
    }
    pTabList = p->pSrc;
    pWhere = p->pWhere;
    if( eDest==SRT_Callback ){
      pOrderBy = p->pOrderBy;

  }

  /* Identify column types if we will be using a callback.  This
  ** step is skipped if the output is going to a destination other
  ** than a callback.
  */
  if( eDest==SRT_Callback ){
    generateColumnTypes(pParse, p->base, pTabList, pEList);
  }

  /* If the output is destined for a temporary table, open that table.
  */
  if( eDest==SRT_TempTable ){
    sqliteVdbeAddOp(v, OP_OpenTemp, iParm, 0);
  }

    sqliteVdbeAddOp(v, OP_OpenTemp, distinct, 1);
  }else{
    distinct = -1;
  }

  /* Begin the database scan
  */
  pWInfo = sqliteWhereBegin(pParse, p->base, pTabList, pWhere, 0, 
                            pGroupBy ? 0 : &pOrderBy);
  if( pWInfo==0 ) goto select_end;

  /* Use the standard inner loop if we are not dealing with
  ** aggregates
  */
  if( !isAgg ){

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.182 2003/04/29 16:20:46 drh Exp $
*/
#include "config.h"
#include "sqlite.h"
#include "hash.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"

** into the second half to give some continuity.
*/
struct WhereInfo {
  Parse *pParse;
  SrcList *pTabList;   /* List of tables in the join */
  int iContinue;       /* Jump here to continue with next record */
  int iBreak;          /* Jump here to break out of the loop */
  int base;            /* Index of first Open opcode */
  int nLevel;          /* Number of nested loop */
  int savedNTab;       /* Value of pParse->nTab before WhereBegin() */
  int peakNTab;        /* Value of pParse->nTab after WhereBegin() */
  WhereLevel a[1];     /* Information about each nest loop in the WHERE */
};

/*

  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  int op;                /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
  Select *pPrior;        /* Prior select in a compound select statement */
  int nLimit, nOffset;   /* LIMIT and OFFSET values.  -1 means not used */
  char *zSelect;         /* Complete text of the SELECT command */
  int base;              /* Index of VDBE cursor for left-most FROM table */
};

/*
** The results of a select can be distributed in several ways.
*/
#define SRT_Callback     1  /* Invoke a callback with each row of result */
#define SRT_Mem          2  /* Store result in a memory cell */

void sqliteDropTable(Parse*, Token*, int);
void sqliteDeleteTable(sqlite*, Table*);
void sqliteInsert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);
IdList *sqliteIdListAppend(IdList*, Token*);
int sqliteIdListIndex(IdList*,const char*);
SrcList *sqliteSrcListAppend(SrcList*, Token*, Token*);
void sqliteSrcListAddAlias(SrcList*, Token*);

void sqliteIdListDelete(IdList*);
void sqliteSrcListDelete(SrcList*);
void sqliteCreateIndex(Parse*,Token*,SrcList*,IdList*,int,int,Token*,Token*);
void sqliteDropIndex(Parse*, SrcList*);
void sqliteAddKeyType(Vdbe*, ExprList*);
void sqliteAddIdxKeyType(Vdbe*, Index*);
int sqliteSelect(Parse*, Select*, int, int, Select*, int, int*);
Select *sqliteSelectNew(ExprList*,SrcList*,Expr*,ExprList*,Expr*,ExprList*,
                        int,int,int);
void sqliteSelectDelete(Select*);
void sqliteSelectUnbind(Select*);
Table *sqliteSrcListLookup(Parse*, SrcList*);
int sqliteIsReadOnly(Parse*, Table*, int);
void sqliteDeleteFrom(Parse*, SrcList*, Expr*);
void sqliteUpdate(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqliteWhereBegin(Parse*, int, SrcList*, Expr*, int, ExprList**);
void sqliteWhereEnd(WhereInfo*);
void sqliteExprCode(Parse*, Expr*);
void sqliteExprIfTrue(Parse*, Expr*, int, int);
void sqliteExprIfFalse(Parse*, Expr*, int, int);
Table *sqliteFindTable(sqlite*,const char*, const char*);
Table *sqliteLocateTable(Parse*,const char*, const char*);
Index *sqliteFindIndex(sqlite*,const char*, const char*);
void sqliteUnlinkAndDeleteIndex(sqlite*,Index*);
void sqliteCopy(Parse*, SrcList*, Token*, Token*, int);
void sqliteVacuum(Parse*, Token*);
int sqliteGlobCompare(const unsigned char*,const unsigned char*);
int sqliteLikeCompare(const unsigned char*,const unsigned char*);
char *sqliteTableNameFromToken(Token*);
int sqliteExprCheck(Parse*, Expr*, int, int*);
int sqliteExprType(Expr*);
int sqliteExprCompare(Expr*, Expr*);
int sqliteFuncId(Token*);
int sqliteExprResolveIds(Parse*, int, SrcList*, ExprList*, Expr*);
int sqliteExprAnalyzeAggregates(Parse*, Expr*);
Vdbe *sqliteGetVdbe(Parse*);
int sqliteRandomByte(void);
int sqliteRandomInteger(void);
void sqliteRollbackAll(sqlite*);
void sqliteCodeVerifySchema(Parse*);
void sqliteBeginTransaction(Parse*, int);

TriggerStep *sqliteTriggerUpdateStep(Token*, ExprList*, Expr*, int);
TriggerStep *sqliteTriggerDeleteStep(Token*, Expr*);
void sqliteDeleteTrigger(Trigger*);
int sqliteJoinType(Parse*, Token*, Token*, Token*);
void sqliteCreateForeignKey(Parse*, IdList*, Token*, IdList*, int);
void sqliteDeferForeignKey(Parse*, int);
#ifndef SQLITE_OMIT_AUTHORIZATION
  void sqliteAuthRead(Parse*,Expr*,SrcList*,int);
  int sqliteAuthCheck(Parse*,int, const char*, const char*, const char*);
  void sqliteAuthContextPush(Parse*, AuthContext*, const char*);
  void sqliteAuthContextPop(AuthContext*);
#else
# define sqliteAuthRead(a,b,c,d)
# define sqliteAuthCheck(a,b,c,d)    SQLITE_OK
# define sqliteAuthContextPush(a,b,c)
# define sqliteAuthContextPop(a)
#endif
void sqliteAttach(Parse*, Token*, Token*);
void sqliteDetach(Parse*, Token*);
int sqliteBtreeFactory(const sqlite *db, const char *zFilename,
                       int mode, int nPg, Btree **ppBtree);

      pTriggerStack->ignoreJump = ignoreJump;
      pParse->trigStack = pTriggerStack;
      sqliteAuthContextPush(pParse, &sContext, pTrigger->name);

      /* code the WHEN clause */
      endTrigger = sqliteVdbeMakeLabel(pParse->pVdbe);
      whenExpr = sqliteExprDup(pTrigger->pWhen);
      if( sqliteExprResolveIds(pParse, 0, &dummyTablist, 0, whenExpr) ){
        pParse->trigStack = pParse->trigStack->pNext;
        sqliteFree(pTriggerStack);
        sqliteExprDelete(whenExpr);
        return 1;
      }
      sqliteExprIfFalse(pParse, whenExpr, endTrigger, 1);
      sqliteExprDelete(whenExpr);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.64 2003/04/25 17:52:11 drh Exp $
*/
#include "sqliteInt.h"

/*
** Process an UPDATE statement.
**
**   UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;

  Table *pTab;           /* The table to be updated */
  int addr;              /* VDBE instruction address of the start of the loop */
  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Vdbe *v;               /* The virtual database engine */
  Index *pIdx;           /* For looping over indices */
  int nIdx;              /* Number of indices that need updating */
  int nIdxTotal;         /* Total number of indices */
  int base;              /* Index of first available table cursor */
  sqlite *db;            /* The database structure */
  Index **apIdx = 0;     /* An array of indices that need updating too */
  char *aIdxUsed = 0;    /* aIdxUsed[i]==1 if the i-th index is used */
  int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
                         ** an expression for the i-th column of the table.
                         ** aXRef[i]==-1 if the i-th column is not changed. */
  int chngRecno;         /* True if the record number is being changed */

  }

  /* Allocate a cursors for the main database table and for all indices.
  ** The index cursors might not be used, but if they are used they
  ** need to occur right after the database cursor.  So go ahead and
  ** allocate enough space, just in case.
  */
  base = pParse->nTab++;
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    pParse->nTab++;
  }

  /* Resolve the column names in all the expressions of the
  ** of the UPDATE statement.  Also find the column index
  ** for each column to be updated in the pChanges array.  For each
  ** column to be updated, make sure we have authorization to change
  ** that column.
  */
  chngRecno = 0;
  for(i=0; i<pChanges->nExpr; i++){
    if( sqliteExprResolveIds(pParse, base, pTabList, 0, pChanges->a[i].pExpr) ){
      goto update_cleanup;
    }
    if( sqliteExprCheck(pParse, pChanges->a[i].pExpr, 0, 0) ){
      goto update_cleanup;
    }
    for(j=0; j<pTab->nCol; j++){
      if( sqliteStrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){

    }
  }

  /* Resolve the column names in all the expressions in the
  ** WHERE clause.
  */
  if( pWhere ){
    if( sqliteExprResolveIds(pParse, base, pTabList, 0, pWhere) ){
      goto update_cleanup;
    }
    if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
      goto update_cleanup;
    }
  }

  /* If we are trying to update a view, construct that view into
  ** a temporary table.
  */
  if( isView ){
    Select *pView;
    pView = sqliteSelectDup(pTab->pSelect);
    sqliteSelect(pParse, pView, SRT_TempTable, base, 0, 0, 0);
    sqliteSelectDelete(pView);
  }

  /* Begin the database scan
  */
  pWInfo = sqliteWhereBegin(pParse, base, pTabList, pWhere, 1, 0);
  if( pWInfo==0 ) goto update_cleanup;

  /* Remember the index of every item to be updated.
  */
  sqliteVdbeAddOp(v, OP_ListWrite, 0, 0);

  /* End the database scan loop.

    /* Open a cursor and make it point to the record that is
    ** being updated.
    */
    sqliteVdbeAddOp(v, OP_Dup, 0, 0);
    if( !isView ){
      sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);
      sqliteVdbeAddOp(v, OP_OpenRead, base, pTab->tnum);
    }
    sqliteVdbeAddOp(v, OP_MoveTo, base, 0);

    /* Generate the OLD table
    */
    sqliteVdbeAddOp(v, OP_Recno, base, 0);
    sqliteVdbeAddOp(v, OP_RowData, base, 0);
    sqliteVdbeAddOp(v, OP_PutIntKey, oldIdx, 0);

    /* Generate the NEW table
    */
    if( chngRecno ){
      sqliteExprCode(pParse, pRecnoExpr);
    }else{
      sqliteVdbeAddOp(v, OP_Recno, base, 0);
    }
    for(i=0; i<pTab->nCol; i++){
      if( i==pTab->iPKey ){
        sqliteVdbeAddOp(v, OP_String, 0, 0);
        continue;
      }
      j = aXRef[i];
      if( j<0 ){
        sqliteVdbeAddOp(v, OP_Column, base, i);
      }else{
        sqliteExprCode(pParse, pChanges->a[j].pExpr);
      }
    }
    sqliteVdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0);
    sqliteVdbeAddOp(v, OP_PutIntKey, newIdx, 0);
    if( !isView ){
      sqliteVdbeAddOp(v, OP_Close, base, 0);
    }

    /* Fire the BEFORE and INSTEAD OF triggers
    */
    if( sqliteCodeRowTrigger(pParse, TK_UPDATE, pChanges, TK_BEFORE, pTab, 
          newIdx, oldIdx, onError, addr) ){
      goto update_cleanup;
    }
  }

  if( !isView ){
    /* 
    ** Open every index that needs updating.  Note that if any
    ** index could potentially invoke a REPLACE conflict resolution 
    ** action, then we need to open all indices because we might need
    ** to be deleting some records.
    */
    sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);
    sqliteVdbeAddOp(v, OP_OpenWrite, base, pTab->tnum);
    if( onError==OE_Replace ){
      openAll = 1;
    }else{
      openAll = 0;
      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
        if( pIdx->onError==OE_Replace ){
          openAll = 1;
          break;
        }
      }
    }
    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
      if( openAll || aIdxUsed[i] ){
        sqliteVdbeAddOp(v, OP_Integer, pIdx->iDb, 0);
        sqliteVdbeAddOp(v, OP_OpenWrite, base+i+1, pIdx->tnum);
        assert( pParse->nTab>base+i+1 );
      }
    }

    /* Loop over every record that needs updating.  We have to load
    ** the old data for each record to be updated because some columns
    ** might not change and we will need to copy the old value.
    ** Also, the old data is needed to delete the old index entires.
    ** So make the cursor point at the old record.
    */
    if( !row_triggers_exist ){
      sqliteVdbeAddOp(v, OP_ListRewind, 0, 0);
      addr = sqliteVdbeAddOp(v, OP_ListRead, 0, 0);
      sqliteVdbeAddOp(v, OP_Dup, 0, 0);
    }
    sqliteVdbeAddOp(v, OP_NotExists, base, addr);

    /* If the record number will change, push the record number as it
    ** will be after the update. (The old record number is currently
    ** on top of the stack.)
    */
    if( chngRecno ){
      sqliteExprCode(pParse, pRecnoExpr);
      sqliteVdbeAddOp(v, OP_MustBeInt, 0, 0);
    }

    /* Compute new data for this record.  
    */
    for(i=0; i<pTab->nCol; i++){
      if( i==pTab->iPKey ){
        sqliteVdbeAddOp(v, OP_String, 0, 0);
        continue;
      }
      j = aXRef[i];
      if( j<0 ){
        sqliteVdbeAddOp(v, OP_Column, base, i);
      }else{
        sqliteExprCode(pParse, pChanges->a[j].pExpr);
      }
    }

    /* Do constraint checks
    */
    sqliteGenerateConstraintChecks(pParse, pTab, base, aIdxUsed, chngRecno, 1,
                                   onError, addr);

    /* Delete the old indices for the current record.
    */
    sqliteGenerateRowIndexDelete(db, v, pTab, base, aIdxUsed);

    /* If changing the record number, delete the old record.
    */
    if( chngRecno ){
      sqliteVdbeAddOp(v, OP_Delete, base, 0);
    }

    /* Create the new index entries and the new record.
    */
    sqliteCompleteInsertion(pParse, pTab, base, aIdxUsed, chngRecno, 1, -1);
  }

  /* Increment the row counter 
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack){
    sqliteVdbeAddOp(v, OP_AddImm, 1, 0);
  }

  /* If there are triggers, close all the cursors after each iteration
  ** through the loop.  The fire the after triggers.
  */
  if( row_triggers_exist ){
    if( !isView ){
      for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
        if( openAll || aIdxUsed[i] )
          sqliteVdbeAddOp(v, OP_Close, base+i+1, 0);
      }
      sqliteVdbeAddOp(v, OP_Close, base, 0);
      pParse->nTab = base;
    }
    if( sqliteCodeRowTrigger(pParse, TK_UPDATE, pChanges, TK_AFTER, pTab, 
          newIdx, oldIdx, onError, addr) ){
      goto update_cleanup;
    }
  }

  /* Repeat the above with the next record to be updated, until
  ** all record selected by the WHERE clause have been updated.
  */
  sqliteVdbeAddOp(v, OP_Goto, 0, addr);
  sqliteVdbeChangeP2(v, addr, sqliteVdbeCurrentAddr(v));
  sqliteVdbeAddOp(v, OP_ListReset, 0, 0);

  /* Close all tables if there were no FOR EACH ROW triggers */
  if( !row_triggers_exist ){
    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
      if( openAll || aIdxUsed[i] ){
        sqliteVdbeAddOp(v, OP_Close, base+i+1, 0);
      }
    }
    sqliteVdbeAddOp(v, OP_Close, base, 0);
    pParse->nTab = base;
  }else{
    sqliteVdbeAddOp(v, OP_Close, newIdx, 0);
    sqliteVdbeAddOp(v, OP_Close, oldIdx, 0);
  }

  sqliteEndWriteOperation(pParse);

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.220 2003/04/25 15:37:58 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The makefile scans this source file and creates the following
** array of string constants which are the names of all VDBE opcodes.

  VERIFY( if( i<0 ) goto bad_instruction; )
  if( expandCursorArraySize(p, i) ) goto no_mem;
  pCx = &p->aCsr[i];
  cleanupCursor(pCx);
  memset(pCx, 0, sizeof(*pCx));
  pCx->nullRow = 1;
  pCx->pseudoTable = 1;
  break;
}

/*
** Opcode: RenameCursor P1 P2 *
**
** Rename cursor number P1 as cursor number P2.  If P2 was previously
** opened is is closed before the renaming occurs.
*/
case OP_RenameCursor: {
  int from = pOp->p1;
  int to = pOp->p2;
  VERIFY( if( from<0 || to<0 ) goto bad_instruction; )
  if( to<p->nCursor && p->aCsr[to].pCursor ){
    cleanupCursor(&p->aCsr[to]);
  }
  expandCursorArraySize(p, to);
  if( from<p->nCursor ){
    memcpy(&p->aCsr[to], &p->aCsr[from], sizeof(p->aCsr[0]));
    memset(&p->aCsr[from], 0, sizeof(p->aCsr[0]));
  }
  break;
}

/* Opcode: Close P1 * *
**
** Close a cursor previously opened as P1.  If P1 is not
** currently open, this instruction is a no-op.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.
**
** $Id: where.c,v 1.77 2003/04/24 01:45:05 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.

                          ** p->pLeft is not the column of any table */
  short int idxRight;     /* p->pRight is a column in this table number. -1 if
                          ** p->pRight is not the column of any table */
  unsigned prereqLeft;    /* Bitmask of tables referenced by p->pLeft */
  unsigned prereqRight;   /* Bitmask of tables referenced by p->pRight */
  unsigned prereqAll;     /* Bitmask of tables referenced by p */
};
















/*
** Determine the number of elements in an array.
*/
#define ARRAYSIZE(X)  (sizeof(X)/sizeof(X[0]))

/*

  }else{
    cnt = exprSplit(nSlot, aSlot, pExpr->pLeft);
    cnt += exprSplit(nSlot-cnt, &aSlot[cnt], pExpr->pRight);
  }
  return cnt;
}

/*



























** This routine walks (recursively) an expression tree and generates
** a bitmask indicating which tables are used in that expression
** tree.  Bit 0 of the mask is set if table base+0 is used.  Bit 1
** is set if table base+1 is used.  And so forth.
**
** In order for this routine to work, the calling function must have
** previously invoked sqliteExprResolveIds() on the expression.  See
** the header comment on that routine for additional information.
**
** "base" is the cursor number (the value of the iTable field) that
** corresponds to the first entry in the list of tables that appear
** in the FROM clause of a SELECT.  For UPDATE and DELETE statements
** there is just a single table with "base" as the cursor number.
*/
static int exprTableUsage(int base, Expr *p){
  unsigned int mask = 0;
  if( p==0 ) return 0;
  if( p->op==TK_COLUMN ){
    return 1<< (p->iTable - base);
  }
  if( p->pRight ){
    mask = exprTableUsage(base, p->pRight);
  }
  if( p->pLeft ){
    mask |= exprTableUsage(base, p->pLeft);
  }
  if( p->pList ){
    int i;
    for(i=0; i<p->pList->nExpr; i++){
      mask |= exprTableUsage(base, p->pList->a[i].pExpr);
    }
  }
  return mask;
}

/*
** Return TRUE if the given operator is one of the operators that is

}

/*
** The input to this routine is an ExprInfo structure with only the
** "p" field filled in.  The job of this routine is to analyze the
** subexpression and populate all the other fields of the ExprInfo
** structure.
**
** "base" is the cursor number (the value of the iTable field) that
** corresponds to the first entry in the table list.
*/
static void exprAnalyze(int base, ExprInfo *pInfo){
  Expr *pExpr = pInfo->p;
  pInfo->prereqLeft = exprTableUsage(base, pExpr->pLeft);
  pInfo->prereqRight = exprTableUsage(base, pExpr->pRight);
  pInfo->prereqAll = exprTableUsage(base, pExpr);
  pInfo->indexable = 0;
  pInfo->idxLeft = -1;
  pInfo->idxRight = -1;
  if( allowedOp(pExpr->op) && (pInfo->prereqRight & pInfo->prereqLeft)==0 ){
    if( pExpr->pRight && pExpr->pRight->op==TK_COLUMN ){
      pInfo->idxRight = pExpr->pRight->iTable - base;
      pInfo->indexable = 1;
    }
    if( pExpr->pLeft->op==TK_COLUMN ){
      pInfo->idxLeft = pExpr->pLeft->iTable - base;
      pInfo->indexable = 1;
    }
  }
}

/*
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the

**          foreach row3 in t3 do   /
**            ...
**          end                     \    Code generated
**        end                        |-- by sqliteWhereEnd()
**      end                         /
**
** There are Btree cursors associated with each table.  t1 uses cursor

** "base".  t2 uses cursor "base+1".  And so forth.  This routine generates
** the code to open those cursors.  sqliteWhereEnd() generates the code
** to close them.
**
** If the WHERE clause is empty, the foreach loops must each scan their
** entire tables.  Thus a three-way join is an O(N^3) operation.  But if
** the tables have indices and there are terms in the WHERE clause that
** refer to those indices, a complete table scan can be avoided and the
** code will run much faster.  Most of the work of this routine is checking
** to see if there are indices that can be used to speed up the loop.

** ORDER BY clause already exists.
**
** If the where clause loops cannot be arranged to provide the correct
** output order, then the *ppOrderBy is unchanged.
*/
WhereInfo *sqliteWhereBegin(
  Parse *pParse,       /* The parser context */
  int base,            /* VDBE cursor index for left-most table in pTabList */
  SrcList *pTabList,   /* A list of all tables to be scanned */
  Expr *pWhere,        /* The WHERE clause */
  int pushKey,         /* If TRUE, leave the table key on the stack */
  ExprList **ppOrderBy /* An ORDER BY clause, or NULL */
){
  int i;                     /* Loop counter */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  int brk, cont;             /* Addresses used during code generation */
  int nExpr;           /* Number of subexpressions in the WHERE clause */
  int loopMask;        /* One bit set for each outer loop */
  int haveKey;         /* True if KEY is on the stack */

  int iDirectEq[32];   /* Term of the form ROWID==X for the N-th table */
  int iDirectLt[32];   /* Term of the form ROWID<X or ROWID<=X */
  int iDirectGt[32];   /* Term of the form ROWID>X or ROWID>=X */
  ExprInfo aExpr[101]; /* The WHERE clause is divided into these expressions */

  /* pushKey is only allowed if there is a single table (as in an INSERT or
  ** UPDATE statement)
  */
  assert( pushKey==0 || pTabList->nSrc==1 );

  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.  If the aExpr[]
  ** array fills up, the last entry might point to an expression which
  ** contains additional unfactored AND operators.
  */

  memset(aExpr, 0, sizeof(aExpr));
  nExpr = exprSplit(ARRAYSIZE(aExpr), aExpr, pWhere);
  if( nExpr==ARRAYSIZE(aExpr) ){
    char zBuf[50];
    sprintf(zBuf, "%d", (int)ARRAYSIZE(aExpr)-1);
    sqliteSetString(&pParse->zErrMsg, "WHERE clause too complex - no more "
       "than ", zBuf, " terms allowed", 0);

  pWInfo = sqliteMalloc( sizeof(WhereInfo) + pTabList->nSrc*sizeof(WhereLevel));
  if( sqlite_malloc_failed ){
    sqliteFree(pWInfo);
    return 0;
  }
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;
  pWInfo->base = base;
  pWInfo->peakNTab = pWInfo->savedNTab = pParse->nTab;
  pWInfo->iBreak = sqliteVdbeMakeLabel(v);

  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (pTabList->nSrc==0 || sqliteExprIsConstant(pWhere)) ){
    sqliteExprIfFalse(pParse, pWhere, pWInfo->iBreak, 1);
    pWhere = 0;
  }

  /* Analyze all of the subexpressions.
  */
  for(i=0; i<nExpr; i++){
    exprAnalyze(base, &aExpr[i]);

    /* If we are executing a trigger body, remove all references to
    ** new.* and old.* tables from the prerequisite masks.
    */
    if( pParse->trigStack ){
      int x;
      if( (x = pParse->trigStack->newIdx) >= 0 ){
        int mask = ~(1 << (x - base));
        aExpr[i].prereqRight &= mask;
        aExpr[i].prereqLeft &= mask;
        aExpr[i].prereqAll &= mask;
      }
      if( (x = pParse->trigStack->oldIdx) >= 0 ){
        int mask = ~(1 << (x - base));
        aExpr[i].prereqRight &= mask;
        aExpr[i].prereqLeft &= mask;
        aExpr[i].prereqAll &= mask;
      }
    }
  }

  ** Actually, if there are more than 32 tables in the join, only the
  ** first 32 tables are candidates for indices.  This is (again) due
  ** to the limit of 32 bits in an integer bitmask.
  */
  loopMask = 0;
  for(i=0; i<pTabList->nSrc && i<ARRAYSIZE(iDirectEq); i++){
    int j;
    int idx = i;

    Table *pTab = pTabList->a[idx].pTab;
    Index *pIdx;
    Index *pBestIdx = 0;
    int bestScore = 0;

    /* Check to see if there is an expression that uses only the
    ** ROWID field of this table.  For terms of the form ROWID==expr
    ** set iDirectEq[i] to the index of the term.  For terms of the
    ** form ROWID<expr or ROWID<=expr set iDirectLt[i] to the term index.
    ** For terms like ROWID>expr or ROWID>=expr set iDirectGt[i].
    **
    ** (Added:) Treat ROWID IN expr like ROWID=expr.
    */
    pWInfo->a[i].iCur = -1;
    iDirectEq[i] = -1;
    iDirectLt[i] = -1;
    iDirectGt[i] = -1;
    for(j=0; j<nExpr; j++){
      if( aExpr[j].idxLeft==idx && aExpr[j].p->pLeft->iColumn<0
            && (aExpr[j].prereqRight & loopMask)==aExpr[j].prereqRight ){
        switch( aExpr[j].p->op ){
          case TK_IN:
          case TK_EQ: iDirectEq[i] = j; break;
          case TK_LE:
          case TK_LT: iDirectLt[i] = j; break;
          case TK_GE:
          case TK_GT: iDirectGt[i] = j;  break;
        }
      }
      if( aExpr[j].idxRight==idx && aExpr[j].p->pRight->iColumn<0
            && (aExpr[j].prereqLeft & loopMask)==aExpr[j].prereqLeft ){
        switch( aExpr[j].p->op ){
          case TK_EQ: iDirectEq[i] = j;  break;
          case TK_LE:
          case TK_LT: iDirectGt[i] = j;  break;
          case TK_GE:
          case TK_GT: iDirectLt[i] = j;  break;
        }
      }
    }
    if( iDirectEq[i]>=0 ){
      loopMask |= 1<<idx;
      pWInfo->a[i].pIdx = 0;
      continue;
    }

    /* Do a search for usable indices.  Leave pBestIdx pointing to
    ** the "best" index.  pBestIdx is left set to NULL if no indices
    ** are usable.

      int ltMask = 0;  /* Index columns covered by an x<... term */
      int gtMask = 0;  /* Index columns covered by an x>... term */
      int inMask = 0;  /* Index columns covered by an x IN .. term */
      int nEq, m, score;

      if( pIdx->nColumn>32 ) continue;  /* Ignore indices too many columns */
      for(j=0; j<nExpr; j++){
        if( aExpr[j].idxLeft==idx 
             && (aExpr[j].prereqRight & loopMask)==aExpr[j].prereqRight ){
          int iColumn = aExpr[j].p->pLeft->iColumn;
          int k;
          for(k=0; k<pIdx->nColumn; k++){
            if( pIdx->aiColumn[k]==iColumn ){
              switch( aExpr[j].p->op ){
                case TK_IN: {

                  break;
                }
              }
              break;
            }
          }
        }
        if( aExpr[j].idxRight==idx 
             && (aExpr[j].prereqLeft & loopMask)==aExpr[j].prereqLeft ){
          int iColumn = aExpr[j].p->pRight->iColumn;
          int k;
          for(k=0; k<pIdx->nColumn; k++){
            if( pIdx->aiColumn[k]==iColumn ){
              switch( aExpr[j].p->op ){
                case TK_EQ: {

        pBestIdx = pIdx;
        bestScore = score;
      }
    }
    pWInfo->a[i].pIdx = pBestIdx;
    pWInfo->a[i].score = bestScore;
    pWInfo->a[i].bRev = 0;
    loopMask |= 1<<idx;
    if( pBestIdx ){
      pWInfo->a[i].iCur = pParse->nTab++;
      pWInfo->peakNTab = pParse->nTab;
    }
  }

  /* Check to see if the ORDER BY clause is or can be satisfied by the

     }else if( iDirectEq[0]>=0 || iDirectLt[0]>=0 || iDirectGt[0]>=0 ){
       /* If the left-most column is accessed using its ROWID, then do
       ** not try to sort by index.
       */
       pSortIdx = 0;
     }else{
       int nEqCol = (pWInfo->a[0].score+4)/8;
       pSortIdx = findSortingIndex(pTab, base, *ppOrderBy, pIdx, nEqCol, &bRev);

     }
     if( pSortIdx && (pIdx==0 || pIdx==pSortIdx) ){
       if( pIdx==0 ){
         pWInfo->a[0].pIdx = pSortIdx;
         pWInfo->a[0].iCur = pParse->nTab++;
         pWInfo->peakNTab = pParse->nTab;
       }
       pWInfo->a[0].bRev = bRev;
       *ppOrderBy = 0;
     }
  }

  /* Open all tables in the pTabList and all indices used by those tables.
  */
  for(i=0; i<pTabList->nSrc; i++){
    Table *pTab;

    pTab = pTabList->a[i].pTab;
    if( pTab->isTransient || pTab->pSelect ) continue;
    sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);
    sqliteVdbeAddOp(v, OP_OpenRead, base+i, pTab->tnum);
    sqliteVdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
    if( i==0 && !pParse->schemaVerified &&
          (pParse->db->flags & SQLITE_InTrans)==0 ){
      sqliteCodeVerifySchema(pParse);
    }
    if( pWInfo->a[i].pIdx!=0 ){
      sqliteVdbeAddOp(v, OP_Integer, pWInfo->a[i].pIdx->iDb, 0);
      sqliteVdbeAddOp(v, OP_OpenRead,
                      pWInfo->a[i].iCur, pWInfo->a[i].pIdx->tnum);
      sqliteVdbeChangeP3(v, -1, pWInfo->a[i].pIdx->zName, P3_STATIC);
    }
  }

  /* Generate the code to do the search
  */
  loopMask = 0;
  for(i=0; i<pTabList->nSrc; i++){
    int j, k;
    int idx = i;
    Index *pIdx;
    WhereLevel *pLevel = &pWInfo->a[i];

    /* If this is the right table of a LEFT OUTER JOIN, allocate and
    ** initialize a memory cell that records if this table matches any
    ** row of the left table of the join.
    */

      **          equality comparison against the ROWID field.  Or
      **          we reference multiple rows using a "rowid IN (...)"
      **          construct.
      */
      k = iDirectEq[i];
      assert( k<nExpr );
      assert( aExpr[k].p!=0 );
      assert( aExpr[k].idxLeft==idx || aExpr[k].idxRight==idx );
      brk = pLevel->brk = sqliteVdbeMakeLabel(v);
      if( aExpr[k].idxLeft==idx ){
        Expr *pX = aExpr[k].p;
        if( pX->op!=TK_IN ){
          sqliteExprCode(pParse, aExpr[k].p->pRight);
        }else if( pX->pList ){
          sqliteVdbeAddOp(v, OP_SetFirst, pX->iTable, brk);
          pLevel->inOp = OP_SetNext;
          pLevel->inP1 = pX->iTable;

      }else{
        sqliteExprCode(pParse, aExpr[k].p->pLeft);
      }
      aExpr[k].p = 0;
      cont = pLevel->cont = sqliteVdbeMakeLabel(v);
      sqliteVdbeAddOp(v, OP_MustBeInt, 1, brk);
      haveKey = 0;
      sqliteVdbeAddOp(v, OP_NotExists, base+idx, brk);
      pLevel->op = OP_Noop;
    }else if( pIdx!=0 && pLevel->score>0 && pLevel->score%4==0 ){
      /* Case 2:  There is an index and all terms of the WHERE clause that
      **          refer to the index use the "==" or "IN" operators.
      */
      int start;
      int testOp;
      int nColumn = (pLevel->score+4)/8;
      brk = pLevel->brk = sqliteVdbeMakeLabel(v);
      for(j=0; j<nColumn; j++){
        for(k=0; k<nExpr; k++){
          Expr *pX = aExpr[k].p;
          if( pX==0 ) continue;
          if( aExpr[k].idxLeft==idx 
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && pX->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            if( pX->op==TK_EQ ){
              sqliteExprCode(pParse, pX->pRight);
              aExpr[k].p = 0;
              break;

                pLevel->inOp = OP_Next;
                pLevel->inP1 = pX->iTable;
              }
              aExpr[k].p = 0;
              break;
            }
          }
          if( aExpr[k].idxRight==idx 
             && aExpr[k].p->op==TK_EQ
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && aExpr[k].p->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, aExpr[k].p->pLeft);
            aExpr[k].p = 0;
            break;

        sqliteVdbeAddOp(v, testOp, pLevel->iCur, brk);
        sqliteVdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
        pLevel->op = OP_Next;
      }
      if( i==pTabList->nSrc-1 && pushKey ){
        haveKey = 1;
      }else{
        sqliteVdbeAddOp(v, OP_MoveTo, base+idx, 0);
        haveKey = 0;
      }
      pLevel->p1 = pLevel->iCur;
      pLevel->p2 = start;
    }else if( i<ARRAYSIZE(iDirectLt) && (iDirectLt[i]>=0 || iDirectGt[i]>=0) ){
      /* Case 3:  We have an inequality comparison against the ROWID field.
      */
      int testOp = OP_Noop;
      int start;

      brk = pLevel->brk = sqliteVdbeMakeLabel(v);
      cont = pLevel->cont = sqliteVdbeMakeLabel(v);
      if( iDirectGt[i]>=0 ){
        k = iDirectGt[i];
        assert( k<nExpr );
        assert( aExpr[k].p!=0 );
        assert( aExpr[k].idxLeft==idx || aExpr[k].idxRight==idx );
        if( aExpr[k].idxLeft==idx ){
          sqliteExprCode(pParse, aExpr[k].p->pRight);
        }else{
          sqliteExprCode(pParse, aExpr[k].p->pLeft);
        }
        sqliteVdbeAddOp(v, OP_MustBeInt, 1, brk);
        if( aExpr[k].p->op==TK_LT || aExpr[k].p->op==TK_GT ){
          sqliteVdbeAddOp(v, OP_AddImm, 1, 0);
        }
        sqliteVdbeAddOp(v, OP_MoveTo, base+idx, brk);
        aExpr[k].p = 0;
      }else{
        sqliteVdbeAddOp(v, OP_Rewind, base+idx, brk);
      }
      if( iDirectLt[i]>=0 ){
        k = iDirectLt[i];
        assert( k<nExpr );
        assert( aExpr[k].p!=0 );
        assert( aExpr[k].idxLeft==idx || aExpr[k].idxRight==idx );
        if( aExpr[k].idxLeft==idx ){
          sqliteExprCode(pParse, aExpr[k].p->pRight);
        }else{
          sqliteExprCode(pParse, aExpr[k].p->pLeft);
        }
        sqliteVdbeAddOp(v, OP_MustBeInt, 1, sqliteVdbeCurrentAddr(v)+1);
        pLevel->iMem = pParse->nMem++;
        sqliteVdbeAddOp(v, OP_MemStore, pLevel->iMem, 0);
        if( aExpr[k].p->op==TK_LT || aExpr[k].p->op==TK_GT ){
          testOp = OP_Ge;
        }else{
          testOp = OP_Gt;
        }
        aExpr[k].p = 0;
      }
      start = sqliteVdbeCurrentAddr(v);
      pLevel->op = OP_Next;
      pLevel->p1 = base+idx;
      pLevel->p2 = start;
      if( testOp!=OP_Noop ){
        sqliteVdbeAddOp(v, OP_Recno, base+idx, 0);
        sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqliteVdbeAddOp(v, testOp, 0, brk);
      }
      haveKey = 0;
    }else if( pIdx==0 ){
      /* Case 4:  There is no usable index.  We must do a complete
      **          scan of the entire database table.
      */
      int start;

      brk = pLevel->brk = sqliteVdbeMakeLabel(v);
      cont = pLevel->cont = sqliteVdbeMakeLabel(v);
      sqliteVdbeAddOp(v, OP_Rewind, base+idx, brk);
      start = sqliteVdbeCurrentAddr(v);
      pLevel->op = OP_Next;
      pLevel->p1 = base+idx;
      pLevel->p2 = start;
      haveKey = 0;
    }else{
      /* Case 5: The WHERE clause term that refers to the right-most
      **         column of the index is an inequality.  For example, if
      **         the index is on (x,y,z) and the WHERE clause is of the
      **         form "x=5 AND y<10" then this case is used.  Only the

      int testOp;

      /* Evaluate the equality constraints
      */
      for(j=0; j<nEqColumn; j++){
        for(k=0; k<nExpr; k++){
          if( aExpr[k].p==0 ) continue;
          if( aExpr[k].idxLeft==idx 
             && aExpr[k].p->op==TK_EQ
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && aExpr[k].p->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, aExpr[k].p->pRight);
            aExpr[k].p = 0;
            break;
          }
          if( aExpr[k].idxRight==idx 
             && aExpr[k].p->op==TK_EQ
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && aExpr[k].p->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, aExpr[k].p->pLeft);
            aExpr[k].p = 0;
            break;

      ** 2002-Dec-04: On a reverse-order scan, the so-called "termination"
      ** key computed here really ends up being the start key.
      */
      if( (score & 1)!=0 ){
        for(k=0; k<nExpr; k++){
          Expr *pExpr = aExpr[k].p;
          if( pExpr==0 ) continue;
          if( aExpr[k].idxLeft==idx 
             && (pExpr->op==TK_LT || pExpr->op==TK_LE)
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && pExpr->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, pExpr->pRight);
            leFlag = pExpr->op==TK_LE;
            aExpr[k].p = 0;
            break;
          }
          if( aExpr[k].idxRight==idx 
             && (pExpr->op==TK_GT || pExpr->op==TK_GE)
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && pExpr->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, pExpr->pLeft);
            leFlag = pExpr->op==TK_GE;
            aExpr[k].p = 0;

      ** 2002-Dec-04: In the case of a reverse-order search, the so-called
      ** "start" key really ends up being used as the termination key.
      */
      if( (score & 2)!=0 ){
        for(k=0; k<nExpr; k++){
          Expr *pExpr = aExpr[k].p;
          if( pExpr==0 ) continue;
          if( aExpr[k].idxLeft==idx 
             && (pExpr->op==TK_GT || pExpr->op==TK_GE)
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && pExpr->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, pExpr->pRight);
            geFlag = pExpr->op==TK_GE;
            aExpr[k].p = 0;
            break;
          }
          if( aExpr[k].idxRight==idx 
             && (pExpr->op==TK_LT || pExpr->op==TK_LE)
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && pExpr->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, pExpr->pLeft);
            geFlag = pExpr->op==TK_LE;
            aExpr[k].p = 0;

        sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqliteVdbeAddOp(v, testOp, pLevel->iCur, brk);
      }
      sqliteVdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
      if( i==pTabList->nSrc-1 && pushKey ){
        haveKey = 1;
      }else{
        sqliteVdbeAddOp(v, OP_MoveTo, base+idx, 0);
        haveKey = 0;
      }

      /* Record the instruction used to terminate the loop.
      */
      pLevel->op = pLevel->bRev ? OP_Prev : OP_Next;
      pLevel->p1 = pLevel->iCur;
      pLevel->p2 = start;
    }
    loopMask |= 1<<idx;

    /* Insert code to test every subexpression that can be completely
    ** computed using the current set of tables.
    */
    for(j=0; j<nExpr; j++){
      if( aExpr[j].p==0 ) continue;
      if( (aExpr[j].prereqAll & loopMask)!=aExpr[j].prereqAll ) continue;
      if( pLevel->iLeftJoin && !ExprHasProperty(aExpr[j].p,EP_FromJoin) ){
        continue;
      }
      if( haveKey ){
        haveKey = 0;
        sqliteVdbeAddOp(v, OP_MoveTo, base+idx, 0);
      }
      sqliteExprIfFalse(pParse, aExpr[j].p, cont, 1);
      aExpr[j].p = 0;
    }
    brk = cont;

    /* For a LEFT OUTER JOIN, generate code that will record the fact that

        if( (aExpr[j].prereqAll & loopMask)!=aExpr[j].prereqAll ) continue;
        if( haveKey ){
          /* Cannot happen.  "haveKey" can only be true if pushKey is true
          ** an pushKey can only be true for DELETE and UPDATE and there are
          ** no outer joins with DELETE and UPDATE.
          */
          haveKey = 0;
          sqliteVdbeAddOp(v, OP_MoveTo, base+idx, 0);
        }
        sqliteExprIfFalse(pParse, aExpr[j].p, cont, 1);
        aExpr[j].p = 0;
      }
    }
  }
  pWInfo->iContinue = cont;
  if( pushKey && !haveKey ){
    sqliteVdbeAddOp(v, OP_Recno, base, 0);
  }

  return pWInfo;
}

/*
** Generate the end of the WHERE loop.  See comments on 
** sqliteWhereBegin() for additional information.
*/
void sqliteWhereEnd(WhereInfo *pWInfo){
  Vdbe *v = pWInfo->pParse->pVdbe;
  int i;
  int base = pWInfo->base;
  WhereLevel *pLevel;
  SrcList *pTabList = pWInfo->pTabList;

  for(i=pTabList->nSrc-1; i>=0; i--){
    pLevel = &pWInfo->a[i];
    sqliteVdbeResolveLabel(v, pLevel->cont);
    if( pLevel->op!=OP_Noop ){
      sqliteVdbeAddOp(v, pLevel->op, pLevel->p1, pLevel->p2);
    }
    sqliteVdbeResolveLabel(v, pLevel->brk);
    if( pLevel->inOp!=OP_Noop ){
      sqliteVdbeAddOp(v, pLevel->inOp, pLevel->inP1, pLevel->inP2);
    }
    if( pLevel->iLeftJoin ){
      int addr;
      addr = sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iLeftJoin, 0);
      sqliteVdbeAddOp(v, OP_NotNull, 1, addr+4 + (pLevel->iCur>=0));
      sqliteVdbeAddOp(v, OP_NullRow, base+i, 0);
      if( pLevel->iCur>=0 ){
        sqliteVdbeAddOp(v, OP_NullRow, pLevel->iCur, 0);
      }
      sqliteVdbeAddOp(v, OP_Goto, 0, pLevel->top);
    }
  }
  sqliteVdbeResolveLabel(v, pWInfo->iBreak);
  for(i=0; i<pTabList->nSrc; i++){
    Table *pTab = pTabList->a[i].pTab;
    assert( pTab!=0 );
    if( pTab->isTransient || pTab->pSelect ) continue;
    pLevel = &pWInfo->a[i];
    sqliteVdbeAddOp(v, OP_Close, base+i, 0);
    if( pLevel->pIdx!=0 ){
      sqliteVdbeAddOp(v, OP_Close, pLevel->iCur, 0);
    }
  }
#if 0  /* Never reuse a cursor */
  if( pWInfo->pParse->nTab==pWInfo->peakNTab ){
    pWInfo->pParse->nTab = pWInfo->savedNTab;
  }
#endif
  sqliteFree(pWInfo);
  return;
}

# 2001 September 15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is in-memory database backend.
#
# $Id: memdb.test,v 1.2 2003/04/20 23:45:23 drh Exp $


set testdir [file dirname $argv0]
source $testdir/tester.tcl

# In the following sequence of tests, compute the MD5 sum of the content
# of a table, make lots of modifications to that table, then do a rollback.

# The following procedure computes a "signature" for table "t3".  If
# T3 changes in any way, the signature should change.  
#
# This is used to test ROLLBACK.  We gather a signature for t3, then
# make lots of changes to t3, then rollback and take another signature.
# The two signatures should be the same.
#
proc signature {} {







  return [db eval {SELECT count(*), md5sum(x) FROM t3}]


}

# Do rollbacks.  Make sure the signature does not change.
#
set limit 10
for {set i 2} {$i<=$limit} {incr i} {
  set ::sig [signature]

  set cnt [lindex $::sig 0]
  set ::journal_format [expr {($i%3)+1}]
  if {$i%2==0} {
    execsql {PRAGMA synchronous=FULL}
  } else {
    execsql {PRAGMA synchronous=NORMAL}
  }
  do_test memdb-1.$i.1-$cnt {
     execsql {
       BEGIN;
       DELETE FROM t3 WHERE random()%10!=0;
       INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
       INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
       ROLLBACK;
     }
     signature
  } $sig


  do_test memdb-1.$i.2-$cnt {
     execsql {
       BEGIN;
       DELETE FROM t3 WHERE random()%10!=0;
       INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
       DELETE FROM t3 WHERE random()%10!=0;
       INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;

# 2002 February 26
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing VIEW statements.
#
# $Id: view.test,v 1.13 2003/04/24 01:45:05 drh Exp $
set testdir [file dirname $argv0]
source $testdir/tester.tcl

do_test view-1.0 {
  execsql {
    CREATE TABLE t1(a,b,c);
    INSERT INTO t1 VALUES(1,2,3);

  }
} 3
do_test view-8.5 {
  execsql {
    SELECT mx+10, mx*2 FROM v8;
  }
} {13 6}











# Tests for a bug found by Michiel de Wit involving ORDER BY in a VIEW.
#
do_test view-9.1 {
  execsql {
    INSERT INTO t2 SELECT * FROM t2 WHERE a<5;
    INSERT INTO t2 SELECT * FROM t2 WHERE a<4;